650sx being punched out to a 686cc..

[rehak2]

Has anyone ever done this? I have the complete top end ready to go but just want to make sure I wont have a clearance problem...and also That I can run the the same crank shaft. I will be running a westcoast head and a sbn 44 carb, full pjs exhaust system. Any input would be great. Thanks guys

 

[ANT]

if it doesnt need to be punched out to a 686 then dont do it. that a little more than 50cc bigger than a stock bore, your sacraficing a lot of reliability doing that and you will most likely be disapointed with the power difference and probably would have to clearance the cases. stick to a 44mmcarb, head, pipe, and prop if you dont already have them and you will have a relaible ski with enough power.